Generally, a replaceable development device for a printer as an image forming apparatus mainly includes a development roller that develops a toner image by attaching toner as developer onto an electrostatic latent image formed on the photosensitive body, a toner supply roller that supplies toner on the development roller, a development blade that regulates a thickness of the toner supplied on the development roller, a charge roller that uniformly and evenly charges the photosensitive body and the like.
In the development device with such a configuration, a surface of a development roller is treated with a urethane solution to give appropriate durability and a stable charge property (e.g. see JP Laid-Open Patent Application No. 2010-152024).
However, it is difficult to obtain a favorable image since it is difficult for developer on a conventional developer carrier to be appropriately charged.
Specific examples illustrated in the present invention aim to improve image quality.